To evaluate the quantitative human mixed lymphocyte culture (MLC) as a predictive test of renal allograft survival. The hypothesis is proposed that the magnitude of the MLC response is inversely related to the length of renal allograft survival in related and unrelated donor recipient pairs. To design a new and "fast" MLC method, the results of which can be determined within 12 to 24 hr after the onset of incubation. Rapid evaluation of the MLC response is important is cadaver transplant matching. The role and mechanism of action of serum albumin as an essential growth factor for lymphocytes in vitro. These studies may provide a key to find mechanisms of growth control of mammalian cells. BIBLIOGRAPHIC REFERENCES: H. Polet, and H. Spieker-Polet: Serum albumin is essential for in vitro growth of activated human lymphocytes. J. Expl. Med. 142, 949, 1975. H. Polet: Role of the cell membrane in the uptake of 3H-actinomycin D by mammalian cells in vitro. J. Pharmacol. Expl. Therap. 192, 270, 1975.